Aquarium Water Chemistry Calculator

Last updated: March 2026

Keep your aquatic friends healthy with precise water parameters

🧪 Water Parameters Checker

Enter your test results to check if levels are safe for your fish.

🔴 Ammonia (NH₃)

🟠 Nitrite (NO₂)

🟡 Nitrate (NO₃)

🟣 pH Level

📋 Safe Parameter Ranges

Parameter Freshwater Saltwater Planted
Ammonia (NH₃) 0 ppm 0 ppm 0 ppm
Nitrite (NO₂) 0 ppm 0 ppm 0 ppm
Nitrate (NO₃) < 40 ppm < 20 ppm < 20 ppm
pH 6.5 - 7.5 8.1 - 8.4 6.5 - 7.2

⚗️ pH Adjustment Calculator

Calculate how much pH buffer you need to reach your target pH.

⚠️ Important Safety Notes

  • Never adjust pH by more than 0.2-0.3 per day
  • Stable pH is better than "perfect" pH
  • Test pH at the same time each day (pH fluctuates)
  • Address the cause (KH, substrate, decor) not just symptoms

💡 Understanding pH Stability

Your water's KH (carbonate hardness) determines pH stability. Low KH = unstable pH. Consider testing and adjusting KH before chasing pH numbers.

💧 Water Change Calculator

Calculate how much water to change to reach your target parameters.

📅 Water Change Guidelines

Scenario Recommended
Lightly stocked tank 10-15% weekly
Moderately stocked 20-25% weekly
Heavily stocked 30-50% weekly
Ammonia/Nitrite spike 50% immediately, then 25% daily
New tank cycling 10-20% if ammonia > 1ppm

💊 Medication Dosing Calculator

Calculate the correct medication dose for your tank.

🔵 Ich-X

White spot disease (Ich)

🌿 Melafix

Bacterial infections, fin rot

🟤 Pimafix

Fungal infections

🟢 API General Cure

Parasites, hex, hole-in-head

🔴 Erythromycin

Bacterial infections, cloudy eye

🧂 Aquarium Salt

Parasites, stress, mild infections

💙 Methylene Blue

Fungus, external parasites, eggs

🪱 PraziPro

Flukes, tapeworms, flatworms

⚠️ Medication Safety

  • Remove activated carbon before medicating
  • Increase aeration during treatment
  • Some meds harm invertebrates and plants
  • Quarantine sick fish when possible
  • Complete the full treatment course

🌡️ Temperature Converter

Convert between Fahrenheit and Celsius for aquarium heating.

🐠 Ideal Temperature Ranges

Fish Type °F °C
Tropical Community 75-80°F 24-27°C
Betta Fish 78-82°F 26-28°C
Goldfish 65-72°F 18-22°C
Discus 82-86°F 28-30°C
African Cichlids 76-82°F 24-28°C
Marine/Reef 75-78°F 24-26°C
Shrimp (Neocaridina) 68-78°F 20-26°C
Axolotl 60-68°F 16-20°C

💡 Temperature Tips

  • Stability is more important than hitting an exact number
  • Avoid temperature swings > 2°F (1°C) per hour
  • Heaters: 3-5 watts per gallon is standard
  • Use a thermometer separate from your heater's gauge